Preheat oven according to cake directions.
Grease a 9x13 baking pan and prepare cake according to box.
While cake is baking, add the sweetened condensed milk and 1/2 cup Kahlua into a microwave safe bowl.
Microwave until the mixture starts to boil, about 1 minute.
Remove from microwave.
Place the chocolate chips into a medium mixing bowl and pour condensed mixture over the chips.
Stir until mixture is smooth and chocolate has melted.
Using the back of a spoon, poke several holes into the top of the cake.
Pour chocolate mixture evenly on top of cake, allowing mixture to seep into holes.
Allow the cake to cool completely in refrigerator.
Once chilled fully, prepare whipped topping by combining all ingredients (minus chocolate chips) into a mixing bowl.
Whip on high with electric mixture until stiff peaks form.
Spread evenly on top of cake and sprinkle additional chocolate chips on top if desired!